title: Comparative evaluation of dental resin composites based on micron- and submicron-sized monomodal glass filler particles.
abstract: OBJECTIVE
  A model resin composite containing a novel monomodal inorganic filler system based on submicron-sized Ba-Si-Al glass particles (NanoFine NF180; Schott) was formulated and compared with an experimental composite containing micron-sized particles (UltraFine UF1.0; Schott).
  
  
  METHODS
  The filler particles were characterized using X-ray microanalysis and granulometry, while the composites were characterized in terms of filler-resin morphology, radiopacity, degree of CC conversion, hardness, flexural strength/modulus, work-of-fracture, surface roughness and gloss (before and after simulated toothbrushing abrasion), and bulk compressive creep. The composites were formulated from the same photoactivated dimethacrylate co-monomer, incorporating mass fractions of 75% micron- and 78% submicron-sized particles. Quantitative data were analyzed at a significance level of p<0.05.
  
  
  RESULTS
  Both filler systems exhibited a narrow grain size range (175±30 and 1000±200 nm), with differences restricted to the size and specific area of the particles. The composites were similar in radiopacity, flexural strength, work-of-fracture, and creep. The submicron composite was harder but had lower flexural modulus and CC conversion. No significant differences in roughness were observed before brushing, although the submicron composite had higher gloss. Brushing increased roughness and decreased gloss on both materials, but the submicron composite retained higher gloss after brushing.
  
  
  CONCLUSIONS
  The monomodal submicron glass filler system demonstrated potential for use in restorative dental composites, particularly due to improved esthetic properties.
authors.affiliation: School of Dentistry, Federal University of Pelotas, Rua Gonçalves Chaves 457, 96015-560 Pelotas, RS, Brazil.
authors.forename: Lisia L
authors.initials: LL
authors.lastname: Valente
authors.forename: Sonia L
authors.initials: SL
authors.lastname: Peralta
authors.forename: Fabrício A
authors.initials: FA
authors.lastname: Ogliari
authors.forename: Larissa M
authors.initials: LM
authors.lastname: Cavalcante
authors.forename: Rafael R
authors.initials: RR
authors.lastname: Moraes
mesh_terms: D000180:Acrylic Resins; D003188:Composite Resins; D005898:Glass; D008855:Microscopy, Electron, Scanning; D011140:Polyurethanes; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D011140:Polyurethanes
keywords: Dental materials; Filler particles; Particle size; Physical and chemical properties; SEM